Drilling equipment of different kinds generate sound, and especially heavy drill equipment such as rock drill rigs used for surface or underground drilling.
Generally, a rock drill rig (FIG. 1) comprises a movable carrier, a boom and a feed beam connected to the boom via e.g. a feed beam holder. The feed beam and the feed beam holder are movable in relation to each other along at least part of the length of the feed beam, to enable relative movement between the feed beam and the boom. A drilling machine is movable along the feed beam, affecting the drill string to be forced into the ground. The drill string comprises the drill point (drill bit) and the joined rods.
Disturbing sound is for instance generated at the drilling machine and at the drill point. It is therefore desirable to dampen the generated sound to the surroundings.
It is known a variety of different sleeves, arranged at the front part of a housing arrangement or feed beam, preventing sound and dust from spreading from the vicinity of the drill hole to the surroundings. These sleeves are often made of rubber or similar materials and arranged annularly around the drill string.
U.S. Pat. No. 3,667,571 discloses an arrangement forming a dust exhaust chamber of an inner truncated cone and an outer cylinder portion leaving an annular space in between. The chamber arrangement rests on the ground by way of two flanges.
WO00/39412 discloses an arrangement made of flexible bristles or strips sealing the one end of a housing to the ground.
WO02/070856 shows a flexible multipart sleeve for contact with the ground being attached to the lower part of a casing.
A problem with known sleeve arrangements is that they impede the visibility/view for the operator when putting the drill point in position. When the operator positions the feed beam with the drill equipment, these sleeves obstruct the view for the operator in the cabin. He/she might have to go out from the cabin to ensure the positioning which of course is time consuming, or even settle for a less favourable position which may result in fatal consequences.